Magnesium and Esophageal Pain After Peroral Endoscopic Myotomy of the Esophagus: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

BACKGROUND: Postoperative esophageal pain occurs in 67% of patients after peroral endoscopic esophageal myotomy (POEM). Magnesium can act as a smooth muscle relaxant. This study investigated whether intraoperative magnesium can reduce postoperative esophageal pain in patients undergoing POEM. METHODS: In this double-blind, placebo-controlled trial, 92 patients were randomized to receive either magnesium sulfate as a 50 mg.kg− 1 (total body weight) bolus followed by an infusion at 25 mg.kg− 1.hr− 1, or 0.9% saline. Intraoperative analgesia was standardized in all patients. The primary outcome was the score from a validated, modified Esophageal Symptoms Questionnaire (ESQ) in the postanesthesia care unit (PACU). Pain scores, opioid requirements, and questionnaire scores were collected through postoperative day 1. RESULTS: ESQ scores were significantly lower in the magnesium group in the PACU (median [25th–75th], 24 [18–31] vs 35 [28–42]; median difference [95% confidence interval, CI], 10 [6–13]; P < .0001) and on postoperative day 1 (16 [14–23] vs 30 [24–35]; P < .0001). Less opioids were needed in the magnesium group in the PACU (mean ± standard deviation [SD] [99% CI], 4.7 ± 10 [1–9] mg vs 29 ± 21 [21–37] mg; P < .0001) and on postoperative day 1 (1 ± 3.7 [0–2.5] mg vs 13 ± 23 [4–23] mg; P = .0009). Pain scores were lower in the magnesium group in the PACU (0 [0–3] vs 5 [5–7]; P < .0001) and on postoperative day 1 (0 [0–2] vs 4 [3–5]; P < .0001). CONCLUSIONS: Patients undergoing POEM randomized to receive intraoperative magnesium had sustained reductions in esophageal discomfort severity and opioid requirements 24 hours after surgery.